The present disclosure generally relates to nanopore devices, such as used for measuring molecular material such as DNA or chemicals, and particularly to a novel field effect based nanopore device for detecting such materials.
Many macromolecules including deoxyribonucleic acid (DNA) have a shape of a linear chain where each Nucleid (AGTC) carries a different electrical charge. For example, a DNA deoxynucleotide carries an electrical charge that is unique for each base and its ability to change a MOSFET threshold voltage has been documented. An ability of a nano-channel to uncoil DNA and translocate DNA has also been demonstrated in the art.
In particular, FIG. 1 illustrates a prior art field effect based sensor device 5 in which a strand of DNA material 9 including combinations of base nucleotide materials (i.e., A (adenine), G (guanine), C (cytosine) and T (thymine) materials) each having unique charges 6 that act as a gate of a conventional planar FET sensor 5 having a planar source 7 and planar drain 8 electrode structures defining a channel there between. In such structures, the chemical nucleotide materials 9 to be sensed act as a gate, and in a detection system, are caused to pass parallel to the wafer substrate above a gate dielectric 11 (e.g., a high-k layer) for sensing action whereby a conduction between the two drain and gate electrodes passing through the chemical is detected.
Many pairs of nucleotides can be detected at once with trade off accuracy and speed, for example, with a combination of 4 nucleotides, there are about 125 possible base nucleotide material combinations in a typical DNA strand rendering just as many distinct voltage or current levels to detect in a FET sensor. FIG. 2 shows a plot 100 of example combinations of DNA base nucleotide materials and their I-V (current to voltage) characteristic as detected by a FET based sensor, and in particular, based on a detected Vt shift of the nucleotide combination.
While a nanopore sensor has been proposed in silicon compound membranes, e.g., silicon nitride, i.e., where a nanopore is a nanoscale sized hole that may, for example, be created by a pore-forming protein or as a hole in synthetic materials such as silicon or grapheme, by basing conduction between the two electrodes passing through the chemical, the measurements have been difficult to detect.